Given that now with Stack Exchange 2.0 the logo of some of the sites, like Web Apps, AskUbuntu, Photography, Gaming and Pro Webmasters have non-white background, I think it will be best if the StackAuth sites route can include the preferred background color for those the logo of these sites.

This is especially important for sites like Photography whose logo is unreadable if the traditional white is used.

Edit: Here's an example of what I mean here:

As you can see, the AskUbuntu logo text totally invisible against a white background.